I'm blown away by how much trouble I'm having with this. There's obviously some assumptions in the API I'm not understanding.

lets say I have a sprite that's 64x64 pixels, and I want to rotate the *center* of this sprite about a point that is outside the sprite itself, expressed in terms of the global coordinate system (ie, top left corner).

How does one go about doing this without calculating the rotations manually?

I've tried playing around with SetOrigin, but I obviously don't know what the purpose of this thing is. The documentation states it's the center for various transformations.

I don't know what it is I'm missing, but this is frustrating, not the least of which is because I could multiply out the transformations myself. I understand the math, I just don't understand what the hell this API is doing.